This invention relates to a method for evaluating venous disease in the lower extremities of the human body.
More specifically, this invention relates to a method for evaluating venous insufficiency, or lack of blood flow through veins in the body in the lower extremities, due to the incompetence of valvular functions or obstructions in the veins.
The evaluation of venous disease in the lower extremities of the body has become more important due to new surgical techniques that have developed for correcting the valvular insufficiency of the veins. Venous insufficiency, or the lack of blood flow in the veins of the lower extremities of the body, typically causes varicose veins, edema, skin pigmentation, claudication, venous ulcers, as well as a great deal of discomfort to the patient. There have been some techniques proposed for the non-invasive examination of venous insufficiency, such as using bi-directional Doppler ultrasonics and radionuclide techniques to study the motion of the blood through the veins of the lower extremities of the body. In one technique, a radioisotope, such as Renografin-60, is slowly injected into the veins of the patient while under fluoroscopic observation, and spot images are obtained of the veins in the leg and thigh.
In order to maintain the proper flow of blood through the veins of the lower extremities of the body, the femoral vein, which is an extension of the inferior vena cava from the heart, contains one or more valves which prevent the blood from descending or reversing flow in the vein during the pumping suction action of the heart. When the valves become damaged, there is an insufficiency of blood flow in the lower extremities, which causes a great deal of discomfort to the patient.
Accordingly, the present invention provides an invasive, non-surgical technique of evaluating venous insufficiency in the deep veins of the lower extremities, that is, the legs and thighs, so that proper surgical techniques can be applied.
In the method of the present invention, which is known as pericarpal percutaneous catheterization, any one of the available veins around the wrist or the distal one-third of the forearm is used for percutaneous catheterization. With this technique, an angiocatheter is introduced into the vein of the arm, which is later substituted for a longer venous catheter with a balloon at the tip and curved end, so that the catheter can be guided through the right atrium of the heart and into the inferior vena cava, and then advanced into the desired iliac vein and placed at the level of the inferior ramus of ischium. An X-ray contrasting material is then injected into the catheter and the competency of the valves and patency of the veins are studied under fluoroscopy. If the valves are incompetent, or not preventing the backflow of the blood in the veins of the leg and thigh, the contrasting material viewed under fluoroscopy will show that the flow is retrograde. With this proper diagnosis, a surgically invasive or non-invasive technique can then be applied to correct the venous insufficiency.
This method of the invention is called the upper extremity approach.
In the prior art there is also other approaches which have a number of disadvantages for the patient. There is the transbrachial catheterization approach wherein a venous cut down is made just above the medial epicondyle of the humerus in the upper arm. The transbreachial approach has many disadvantages since it requires the insertion of a catheter into deep veins which therefore requires surgery and causes a great deal of discomfort to the patient.
In the prior art there is also the transcervical approach wherein the internal jugular or subclavian vein receives the guide wire and venous catheter for performing the examination. This has the disadvantage of being a blind approach with danger and risk of causing injury to the lungs including puncturing the lungs with the guide wire causing an air leak in the chest. There is also a great deal of bleeding that occurs in the transcervical approach.
Another conventional approach for venous examination is the transgroin approach which is also a blind procedure. Whether the transgroin approach is contralateral or ipsilateral this approach runs a high risk of injuring the arteries and producing blood clots in the veins.
The present invention provides many advantages over the conventional approaches by utilizing a superficial vein located around the wrist or in the forearm where is little or no danger of creating blood clots, puncturing the lungs or requiring any deep invasive surgery. The upper extremity approach of the present invention according to the invention was made possible by significantly reducing the diameter of the catheter so that it would experience little or no obstruction as it advanced through the superficial vein and ultimately through the femoral vein in the groin. More over, the invention utilizes a catheter and guide wire that have been greatly elongated over conventional catheters and guide wires in order to facilitate the longer distances in which the catheter and guide wire have to travel before they reach the distal part of the femoral vein.
Accordingly, it is an object of the present invention to provide a method for diagnosing all types of chronic venous insufficiency.
It is another object, according to the present invention, to provide an improved method for diagnosing chronic venous insufficiency using interchangeable catheters to more precisely locate, evaluate and determine the amount of insufficiency of the veins of the lower extremities of the body.
It is another object, according to the present invention, to diagnose venous insufficiency due to venous thrombosis and to provide a method for retrograde catheterization of the venous tree to retrieve venous blood clots.
Other objects and features of the present invention will become apparent from the following detailed description considered in connection with the accompanying drawings which disclose the embodiments and method of the present invention.